class_docstr: A memoizing mapping that retains `capacity` deleted items
  
  The memo tracks retained items by their access order; once `capacity` items
  are retained, the least recently used item is discarded.
code: def __getitem__(self, key):
      try:
          return self._active[key]
      except KeyError:
          self._memory.move_to_end(key)
          return self._memory[key]
  
imports: import inspect
  import warnings
  import types
  import collections
  import itertools
  from functools import lru_cache, wraps
  from typing import Callable, List, Union, Iterable, TypeVar, cast
label_desc: Use image node_id 2 for calling the LRUMemo obj's underlying member method code with example usage: obj.__getitem__(key) and returns: self, self